Disease-related concerns:• Arrhythmias: Use with caution in patients who may be at risk of cardiac arrhythmias.• Kidney stones (calcium-containing): Use caution when administering calcium supplements to patients with a history of kidney stones.

Sodium Polystyrene Sulfonate: Antacids may enhance the adverse/toxic effect of Sodium Polystyrene Sulfonate. The combined use of these two agents may result in metabolic alkalosis and/or loss of efficacy of the exchange resin. Management: To minimize this interaction, consider: a)separating doses by 2 or more hours; b)rectal administration of the exchange resin; or c)alternatives to antacids. Monitor for metabolic alkalosis and attenuation of SPS effects. Avoid magnesium hydroxide. Risk D: Consider therapy modificationTetracycline Derivatives: Calcium Salts may decrease the serum concentration of Tetracycline Derivatives. Management: If coadministration of oral calcium with oral tetracyclines can not be avoided, consider separating administration of each agent by several hours. Risk D: Consider therapy modification

Thyroid Products: Calcium Salts may diminish the therapeutic effect of Thyroid Products. Management: Separate the doses of the thyroid product and the oral calcium supplement by at least 4 hours. Risk D: Consider therapy modification*** List is not comprehensive, please seek further interaction software where concerned. Risk D or X only included***

Mechanism of ActionUsed to treat hyperphosphatemia in patients with advanced renal insufficiency by combining with dietary phosphate to form insoluble calcium phosphate, which is excreted in feces. Patient EducationTake with meals. Avoid alcohol. May cause constipation or dry mouth. Report severe, unresolved GI disturbances.

Pharmacodynamics/KineticsExcretion: Primarily feces (as unabsorbed calcium); urine (20%)Pharmacotherapy Pearls20 mEq calcium/g; 400 mg elemental calcium/g calcium carbonate (40% elemental calcium)Cardiovascular ConsiderationsHypercalcemia is evident on ECG by shortening of the QT interval and possibly lengthening of the PR interval. Hypocalcemia causes prolongation of the QT interval. This prolongation is due to lengthening of the ST segment; the T waves remain unchanged. However, in severe hypocalcemia, T waves may be inverted. Note that only hypocalcemia and hypothermia lengthen the ST segment without altering T-wave duration. Hypocalcemia may also present clinically with skeletal muscle spasm.Calcium salts may enhance the arrhythmogenic effects of digoxin. Part of the inotropic action of digoxin appears to be associated with increased intracellular calcium availability. Chronotropic effects are also calcium mediated. The administration of exogenous calcium (especially by parenteral routes) can lead to cardiac arrhythmias.

Calcium Acetate

** Listed below are differences from above**

*** Calcium Acetate is not commonly used in Canada as a phosphate binder***Dosing: Control of hyperphosphatemia (ESRD, on dialysis): Oral: Initial: 1334 mg with each meal, can be increased gradually (ie, every 2-3 weeks) to bring the serum phosphate value < 1.8 mmol/L as long as hypercalcemia does not develop (usual dose: 2001-2668 mg calcium acetate with each meal); do not give additional calcium supplements